I bought a used set of BBS E88 wheels while here in Germany. The owner was the original owner who had them spec'd for a 964 widebody turbo but the specs were about identical for my 997.1 S (narrowbody) so I pulled the trigger for a great deal (and good story). They've since been mounted, raced, ran and autobahned with no issues. However, I want to get the lips re-finished and possibly get new sizing while I'm at it. This is where I need your help BBS gurus, I have part numbers but no exact offset for these and want to know the current offset and what size I should go for next (for the fronts).

Specs are as follows:
18x9 +40?
Part numbers and size:
01 82 042 1212 (18 x 1 1/2) LIP
01 82 054 1112 (18 x 7 1/2) BARREL

18x11 +60?
01 82 044 1212 (18 x 2 1/2) LIP
01 83 056 0812 (18 x 8 1/2) BARREL

Additional question, I'd like to resize the front to more of a 997 narrowbody friendly sizing. Ideally (opinions welcome), up front:
18x9 +45-50 or 18x8.5 +40-45 ???
What part number (lip) would I need to buy to accomplish this? I plan on having them re-done if its worth it.

Please and thanks BBS gurus!